So why not boil/clean/sterilize adapters and reuse them?

[lewichuk19]

Thank you Dave and Tim, that makes sense.

[DrTimPerkins]

The worst place to harbor those microbes is the tap, thus change every year, second worst is thew drop, thus replace it every 2-3 seasons. The lateral line does not seem to be the issue a drop is, that should be good for the life of the tubing.

If you want more information on it, that is exactly the subject of the papers at http://www.uvm.edu/~pmrc/aging.pdf and http://www.uvm.edu/~pmrc/tubing_age.pdf The story is slightly different (more exaggerated) with 3/16" tubing due to the increased susceptibility (in some ways) to backflow-related sanitation issues.

In essence, the spout is the most important component to keep clean, the dropline next (unless you are using CV spouts/adapters), and the lateral line and mainline are really not at all important in terms of sanitation-related yield concerns. What it all boils down to is that the cleanliness of the spout is of primary importance because most of the contamination of the taphole is related to the spout due to very small perturbations in vacuum causing periodic movement of sap backward from the spout/tubing into the taphole (backflow). Of secondary importance is the dropline, because, more rarely, larger leaks or system shutdowns can result in sap moving from a few feet away back into the taphole. This is less frequent though, so the dropline sanitation level is less critical, but still important. It is very rare for sap to flow from the lateral line (or mainline) all the way back into the taphole, so sanitation level there is not really important (in terms of sap yield reductions). Thus changing spouts annually and droplines periodically (every 2-3 yrs), or using CV spouts/adapters (which negates the need to change droplines as often) will result in the highest yields.

With 3/16" systems, the problem does extend a bit further along, so lateral line sanitation is somewhat more important.

It's a bit funny to me, but fulfilling as well, to hear people talk about this so much like it is common knowledge. Ten years ago it was not the case. It took quite a number of years of research and quite a bit of grant funding, and a lot of papers and presentations to get to where we are. I've spent a good deal of my career looking at this stuff, but have seen the industry go from talking about good yields being 0.3 gal syrup/tap to now over 0.5 gal/tap or higher (the UVM PMRC average from 2004-2017 is 0.59 gal/tap).

More on the subject of sanitation at http://www.uvm.edu/~pmrc/?Page=checkvalves.htm and others under "Recent Publications" at http://www.uvm.edu/pmrc

[Biz]

I assume for us with battery powered pumps that get turned off every night, the problem is worse? If so then CV spouts may be essential after the first year then, if good sanitation is even possible with this type of pump.

On my short runs of 3/16 tubing with 20-40 taps on a diaphragm pump, I'm planning on CV spouts and 5/16 drops to the adaptor tees. The pump will get turned off after the sap has stopped flowing and vacuum drops. These all seem like they should help but wondering if this type of setup has any chance of getting high yields per tap?

Dave

[markcasper]

If you want more information on it, that is exactly the subject of the papers at http://www.uvm.edu/~pmrc/aging.pdf and http://www.uvm.edu/~pmrc/tubing_age.pdf The story is slightly different (more exaggerated) with 3/16" tubing due to the increased susceptibility (in some ways) to backflow-related sanitation issues.

In essence, the spout is the most important component to keep clean, the dropline next (unless you are using CV spouts/adapters), and the lateral line and mainline are really not at all important in terms of sanitation-related yield concerns. What it all boils down to is that the cleanliness of the spout is of primary importance because most of the contamination of the taphole is related to the spout due to very small perturbations in vacuum causing periodic movement of sap backward from the spout/tubing into the taphole (backflow). Of secondary importance is the dropline, because, more rarely, larger leaks or system shutdowns can result in sap moving from a few feet away back into the taphole. This is less frequent though, so the dropline sanitation level is less critical, but still important. It is very rare for sap to flow from the lateral line (or mainline) all the way back into the taphole, so sanitation level there is not really important (in terms of sap yield reductions). Thus changing spouts annually and droplines periodically (every 2-3 yrs), or using CV spouts/adapters (which negates the need to change droplines as often) will result in the highest yields.

With 3/16" systems, the problem does extend a bit further along, so lateral line sanitation is somewhat more important.

It's a bit funny to me, but fulfilling as well, to hear people talk about this so much like it is common knowledge. Ten years ago it was not the case. It took quite a number of years of research and quite a bit of grant funding, and a lot of papers and presentations to get to where we are. I've spent a good deal of my career looking at this stuff, but have seen the industry go from talking about good yields being 0.3 gal syrup/tap to now over 0.5 gal/tap or higher (the UVM PMRC average from 2004-2017 is 0.59 gal/tap).

More on the subject of sanitation at http://www.uvm.edu/~pmrc/?Page=checkvalves.htm and others under "Recent Publications" at http://www.uvm.edu/pmrc

Tim, you brought up a thing that has refreshed my memory yet again. That being, at least once or twice per season, if not up to 1/2 dozen times, I have had the mainline fill up. freeze, and the whole system backs up to the point where many drops fill up all the way back to the tap. In one of my bushes especially, most of the large mainline is located in the coolest part of the woods, in the valley, while the tress and lats are on southerly slopes, up higher. For example. Last spring....I was tapping during a heavy run day (and lost it all), by 2 oclock in the morning when I finished tapping, the weather had turned below freezing, the trees ran solid until freeze up, I witnessed the sap backing up into the laterals, then the drops, and eventually running right out around the spout. The trees were warmer and wanted to keep running. So, the question is, isn't the use of a new checkvalve or tap already compromised and the whole contaminated? I have had this happen in all of my woods before and it is not because it does not have enough slope. You could have 10% slope and with the trees running as hard as they do sometimes, then you get a very sudden freeze up, the sap will not ever be able to drain fast enough.

[Mark]

Tim, you brought up a thing that has refreshed my memory yet again. That being, at least once or twice per season, if not up to 1/2 dozen times, I have had the mainline fill up. freeze, and the whole system backs up to the point where many drops fill up all the way back to the tap. In one of my bushes especially, most of the large mainline is located in the coolest part of the woods, in the valley, while the tress and lats are on southerly slopes, up higher. For example. Last spring....I was tapping during a heavy run day (and lost it all), by 2 oclock in the morning when I finished tapping, the weather had turned below freezing, the trees ran solid until freeze up, I witnessed the sap backing up into the laterals, then the drops, and eventually running right out around the spout. The trees were warmer and wanted to keep running. So, the question is, isn't the use of a new checkvalve or tap already compromised and the whole contaminated? I have had this happen in all of my woods before and it is not because it does not have enough slope. You could have 10% slope and with the trees running as hard as they do sometimes, then you get a very sudden freeze up, the sap will not ever be able to drain fast enough.

I have seen that happen when there is a leak at a multi fitting and it freezes the main up. When I put in the Smartrek system I was shocked to see what goes on in the bush. Before freeze up lines start going to zero vacuum and sometimes even pressurize. I keep track of which ones and the next day you can usually find the problem.

[DrTimPerkins]

...I witnessed the sap backing up into the laterals, then the drops, and eventually running right out around the spout. The trees were warmer and wanted to keep running. So, the question is, isn't the use of a new checkvalve or tap already compromised and the whole contaminated?

Although that could happen, it seems like a fairly unusual (at least not common) type of thing. Seems like perhaps your mainline either runs through a really cold spot or maybe has a high spot somewhere that doesn't allow it to drain properly. Either way, yes, it could result in backflow. However, keep in mind that if the trees are still thawed and sap is running then it means that there is PRESSURE within the tree for a good period of time as the lines freeze up, thus there should not be much of any sap moving backward at this time.

[markcasper]

Although that could happen, it seems like a fairly unusual (at least not common) type of thing. Seems like perhaps your mainline either runs through a really cold spot or maybe has a high spot somewhere that doesn't allow it to drain properly. Either way, yes, it could result in backflow. However, keep in mind that if the trees are still thawed and sap is running then it means that there is PRESSURE within the tree for a good period of time as the lines freeze up, thus there should not be much of any sap moving backward at this time.

Yes, there is some cold spots, BUT its not b/c the line has a dip in it. Doesn't help that there is only 2% slope in some areas. I have seen my other woods with a 500 ft. section of mainline, north side @ 2% slope with icicles hanging off practically EVERY saddle, and red maple taps that were untapped and capped off (end of season 2016) at the T blown off in the morning up to 50 ft from the mainline. Conditions prior to this were a HEAVY run day which continued right into the night when it froze up hard and fast. No possible way those lines will drain under these conditions. And like most of us, the releaser and tanks are located in the area of the bush that will freeze up first.

[WestfordSugarworks]

Unless you have a leak somewhere on the line. After a period of time on vacuum, vacuum is transferred into the vessels of the wood in the tree. So let's say you have 29" Hg vacuum in the line, and get a squirrel chew about 10' down the line or a fitting pops off somewhere. Under those conditions, the driving force of the vacuum is lost at that point in the line, and the vacuum in the line at that point is 0" Hg. You still have 29" Hg of vacuum IN THE TREE. Which way do you think sap will run? Hint....it isn't down. Nope...it'll run right back into the taphole, where the wood fibers around the inner part of taphole form a nice filter for all the microbes coming back from the tubing, leaving a nice coating of microbes all around the inner surface of the taphole. The tree senses these microbes, and to stave off infection, starts the wound-response process of closing off (walling off) the taphole, which happens far more quickly than most people think....a matter of weeks it becomes noticeable if carefully measured. Unfortunately, the reality is that due to the diameter of the tubing, sap in a 3/16" tubing system will run back WAY further than in a 5/16" system...on the order of tens of feet rather than a few feet. What is more common on 5/16" systems is pulses of backflow (on the order of inches) due to the introduction of air when a mechanical releaser dumps. You can see this happening at https://www.youtube.com/watch?v=__9xGeunEK8 An electric releaser avoids this (mostly), but is still susceptible to leak-induced backflow.

Dr. Tim, thanks for sharing this post. I had no idea that vacuum actually exists within the tree after sustained high vacuum from the tubing system. If I find a tree that is leaking during the season (tapped by someone without a good eye for what good shavings should look like) and can't find any good wood when I try to redrill, I will pull the dropline off and put in a 5/16" connector. When I do this there is a vacuum leak for a few seconds while I add in the fitting. Maybe I would do better to wire tie the dropline closed (kink it and wire tie) so that it can no longer leak and then remove it while pulling spouts, to prevent the issues you mention in your post.

Thanks for all you share with us.

[Walling's Maple Syrup]

Dr. Tim, thanks for sharing this post. I had no idea that vacuum actually exists within the tree after sustained high vacuum from the tubing system. If I find a tree that is leaking during the season (tapped by someone without a good eye for what good shavings should look like) and can't find any good wood when I try to redrill, I will pull the dropline off and put in a 5/16" connector. When I do this there is a vacuum leak for a few seconds while I add in the fitting. Maybe I would do better to wire tie the dropline closed (kink it and wire tie) so that it can no longer leak and then remove it while pulling spouts, to prevent the issues you mention in your post.

Thanks for all you share with us.

I carry a few pairs of needle noses vice grips in my "fix bag" when I am looking for leaks. When I find one, I clamp tubing on every side of leak before I fix it. This keeps the vacuum from being disrupted. Slide some pieces of 5/16" tubing over ends of vice grips so it doesn't damage tubing.
Neil

[berkshires]

Dr Tim, how much of this holds true for taps into buckets, without drop lines? Is it safe to assume that open taps will allow the tree to get infected pretty quickly? In other words, I would think that (unless it's really bad) the condition of the spile is not going to be the primary issue in infecting the tree.

So if I just clean my spiles with soapy water and then sterilize with bleach each year, I can probably keep using the same taps for several years without seeing a noticeable change in how quickly holes dry up?

Gabe